Generally, a heat-insulating housing of a refrigerator is formed of a layered body including a steel (including iron and cast iron) plate as an outer wall material, a resin plate as an inner wall material and a heat insulator interposed between the steel plate and the resin plate. The heat insulator is made of urethane foam or the like, and chlorofluorocarbons are used as a foaming agent therefor. Since chlorofluorocarbons may destroy an ozone layer, it is necessary to collect them at the time of disposing of a refrigerator and prevent them from diffusing into the air. It also is desired that the steel plate and the resin plate should be collected for recycling.
As a conventional method for disassembling a discarded refrigerator, a method described in JP 2679562 B is known, for example. The following is a brief description of this method.
After a steel plate and a resin plate are removed from a heat-insulating housing, urethane foam first is cut into pieces of approximately 5 cm square, which are put into a hopper and sent to a crusher. In the process where external mechanical force is applied in the crusher so as to crush the urethane foam, closed-cells therein are destroyed. Chlorofluorocarbons released from the closed-cells and the crushed urethane grains are sent to a bag filter together with the air, so that a gaseous component and the urethane grains are separated. The gaseous component is cooled down in a condenser, so that the chlorofluorocarbons are liquefied and separated, and then the gas that is not condensed is sent back to the hopper. In this manner, the chlorofluorocarbons contained in the urethane foam can be separated and collected without being diffused into the air.
However, in the above-described disassembling method, after crushing the urethane foam, in order to separate the urethane grains and the released chlorofluorocarbons, a mixture thereof is sent with the air to the bag filter, so that they are separated by utilizing a wind power. Thus, since the chlorofluorocarbons are diffused in the carrier air, the concentration of the chlorofluorocarbons becomes extremely low. Under such conditions, the condensation and separation of the chlorofluorocarbons is by no means efficient. Furthermore, the equipment for carrying out these processes is large, raising equipment costs considerably.
Moreover, both the crusher for crushing the urethane foam and the separator for separating the urethane grains and the gaseous component generally are very large, which require a large installation space and cost much.